Anecdotes and the shifting baseline syndrome of fisheries.
TL;DR: F isheries have recently become a topic for media with global audiences-but then again, fisheries are a global disaster: one of the few that affect, in very similar fashion, developed countries with well-established administrative and scientific infrastructure, newly industrialized countries, and developing countries.
Abstract: F isheries have recently become a topic for media with global audiences-but then again, fisheries are a global disaster: one of the few that affect, in very similar fashion, developed countries with well-established administrative and scientific infrastructure, newly industrialized countries , and developing countries. This is quickly summarized: l Heavily subsidized fleets, exceeding by a factor of 2 or 3 the numbers required to harvest nominal annual catches of about 90 million tonnes. l Staggering levels of discarded bycatch, representing about one third of the nominal catch, a large unrecorded catch that perhaps raises the true global catch to about 150 million tonnes per year, well past most previous estimates of global potential. l The collapse, depletion or recovery from previous depletion of the overwhelming majority of the over 260 fish stocks that are monitored by the Food and Agriculture Organization of the United Nations. Fisheries science has responded as well as it could to the challenge this poses by developing methods for estimating targets for management-earlier the fabled Maximum Sustainable Yield (MSY)l, now annual total allowable catch (TAC) or individual transferable quotas (ITQ). If these methods are to remain effective, fisheries scientists need to follow closely the behavior of fishers and fleets, but this has tended increasingly to separate us from the biologists studying marine or freshwater organisms and/or communities, and to factor out ecological and evolutionary considerations from our models. There are obviously exceptions to this, but 1 believe the rule generally applies, and it can be illustrated by our lack of an explicit model accounting for what may be called the 'shifting baseline syndrome'. Essentially, this syndrome has arisen because each generation of fisheries scientists accepts as a baseline the stock size and species composition that occurred at the beginning of their careers, and uses this to evaluate changes. When the next generation starts its career, the stocks have further declined, but it is the stocks at that time that serve as a new baseline. The result obviously is a gradual shift of the baseline, a gradual accommodation of the creeping disappearance of resource species, and inappropriate reference points for evaluating economic losses resulting from overfishing, or for identifying targets for rehabilitation measures. These are strong claims that 1 can illustrate best by using analogies. For example, astronomy has a framework that uses ancient observations (including Sumerian and Chinese records that are thousands of years old) of …
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Abstract: ▪ Abstract We review the evidence of regime shifts in terrestrial and aquatic environments in relation to resilience of complex adaptive ecosystems and the functional roles of biological diversity in this context. The evidence reveals that the likelihood of regime shifts may increase when humans reduce resilience by such actions as removing response diversity, removing whole functional groups of species, or removing whole trophic levels; impacting on ecosystems via emissions of waste and pollutants and climate change; and altering the magnitude, frequency, and duration of disturbance regimes. The combined and often synergistic effects of those pressures can make ecosystems more vulnerable to changes that previously could be absorbed. As a consequence, ecosystems may suddenly shift from desired to less desired states in their capacity to generate ecosystem services. Active adaptive management and governance of resilience will be required to sustain desired ecosystem states and transform degraded ecosystems...
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Cites background from "Anecdotes and the shifting baseline..."
...Typically, the stocks continue to decline even further, and over time management targets slip lower and lower, a scenario known as “the shifting baseline&rdquo...
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TL;DR: Zoning the oceans into unfished marine reserves and areas with limited levels of fishing effort would allow sustainable fisheries, based on resources embedded in functional, diverse ecosystems.
Abstract: Fisheries have rarely been 'sustainable'. Rather, fishing has induced serial depletions, long masked by improved technology, geographic expansion and exploitation of previously spurned species lower in the food web. With global catches declining since the late 1980s, continuation of present trends will lead to supply shortfall, for which aquaculture cannot be expected to compensate, and may well exacerbate. Reducing fishing capacity to appropriate levels will require strong reductions of subsidies. Zoning the oceans into unfished marine reserves and areas with limited levels of fishing effort would allow sustainable fisheries, based on resources embedded in functional, diverse ecosystems.
2,896 citations
Cites background from "Anecdotes and the shifting baseline..."
...It is difficult to fully appreciate the extent of the changes to ecosystems that fishing has wrought, given shifting baselines as to what is considered a pristine ecosyste...
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TL;DR: The analysis suggests that management based on recent data alone may be misleading, and provides minimum estimates for unexploited communities, which could serve as the 'missing baseline' needed for future restoration efforts.
Abstract: Serious concerns have been raised about the ecological effects of industrialized fishing1, 2, 3, spurring a United Nations resolution on restoring fisheries and marine ecosystems to healthy levels4. However, a prerequisite for restoration is a general understanding of the composition and abundance of unexploited fish communities, relative to contemporary ones. We constructed trajectories of community biomass and composition of large predatory fishes in four continental shelf and nine oceanic systems, using all available data from the beginning of exploitation. Industrialized fisheries typically reduced community biomass by 80% within 15 years of exploitation. Compensatory increases in fast-growing species were observed, but often reversed within a decade. Using a meta-analytic approach, we estimate that large predatory fish biomass today is only about 10% of pre-industrial levels. We conclude that declines of large predators in coastal regions5 have extended throughout the global ocean, with potentially serious consequences for ecosystems5, 6, 7. Our analysis suggests that management based on recent data alone may be misleading, and provides minimum estimates for unexploited communities, which could serve as the ‘missing baseline’8 needed for future restoration efforts.
2,864 citations
Cites methods from "Anecdotes and the shifting baseline..."
...Our analysis suggests that management based on recent data alone may be misleading, and provides minimum estimates for unexploited communities, which could serve as the ‘missing baseline&rsquo...
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TL;DR: The paper summarizes the capabilities of the modeling system with respect to evaluating how fisheries and the environment impact ecosystems and presents an overview of the computational aspects of the Ecopath, Ecosim and Ecospace modules as they are implemented in the most recent software version.
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TL;DR: In this paper, the authors show that women contribute significantly to marine food yields in the region and suggest that the highly regular nature of women's fishing makes women more reliable, and therefore more effective than men as suppliers of protein for subsistence.
Abstract: Women's fishing in Oceania has been overlooked in most subsistence studies in the region and, as a consequence, there are few quantitative data available upon which to base an assessment of its importance. However, in the present study, the few data available on women's fishing in Oceania are examined, and these show that women contribute significantly to marine food yields in the region. Also, it is suggested that the highly regular nature of women's fishing makes women more reliable, and therefore more effective than men as suppliers of protein for subsistence. The implications of these findings for future development policies in the region are then discussed.
130 citations